2018 Current Trends in Raising Soybeans in Pennsylvania

Numerous growers question what is the current trends in raising soybeans in Pennsylvania. This is not an easy question since it depends on where in Pennsylvania one wishes to grow soybeans. One reason Penn State is involved with the Soybean Contest is that as educators we get to view what practices seem to promote these high yields and clues can be obtained by knowing key practices. The Agronomy Guide Soybean Production Section details our current recommendations in detail and offers regional advice. Here are eight highlights that may prove useful in growers production systems.

1. Soil Management (Soil Test not less than 3 years old)

Soil Test! Many top growers are testing yearly. At least have a soil test within 3 years.

Maintain a pH of 6.8 but not higher than 7.2

If less than 6.8 utilize .25lb/acre of sodium molybdate either on the seed or applied before V2 On Station and with the PA Soybean On Farm Network have demonstrated significant yield results with the inclusion of moly in low pH environments.

Many growers in the PA Soybean Contest inoculate seed with rhizobium regardless of history. Penn State recommends inoculation every 5 years with a history of soybeans however, with recent improvement in rhizobium more work needs to be explored in this area.

Maintain phosphorus and potassium levels in the optimum range.

Check compaction in the spring and avoid side wall compaction by adjusting planting date so as to ensure soil is dry enough to plant into.

2. Rotations

Rotate with a grass seems to aid in production. Growers (70%) in the PA Soybean Contest use cover crops of wheat or barley and rotations with corn. Further recent work in the PA On Farm Network has shown significant yield differences with soybeans grown after a cover crop vs left untreated.

3. Variety Selection

Get to know a variety and what it requires. Some varieties tend to prefer higher seeding rates and some lower, some need to be harvested early as the pods maybe more prone to shatter loss. In Penn State Soybean Performance trials in a typical year yields vary 18 bushel per acre or more within a maturity. Numerous pest resistance packages are unique to varieties and growers need to make selections based on the field in question and diseases that may be present in the field.

Many growers and Penn State research have shown that in many cases early maturing soybeans in the southeast tend to outperform full season with respect to timing grain fill periods to late season rains.

4. Seeding Rate

Soybeans are capable of tremendous yields even at ultra low populations due to the innate ability to produce additional pods and branching. Seed drop will vary by soil conditions and tillage practices. Optimum yields are confirmed at seeding rates of 140,000 and even less on certain soil types. To that end final stands in the 100-120,000 ppa range have been a standard target in most environments. The grower needs to make the decision as what rate to drop to achieve a final stand at harvest of 100- 120,000 ppa for most varieties. In most situations dropping 140-180,000ppa seed drop at planting will meet the needs for full season early to mid season plantings. Late and or double crop plantings should be much higher in the 200-225,000ppa ranges due to the influence of sunlight on the plants ability to gain height and flowers later in the season.

5. Planting Date and Row Width

For early planting row width is not as important however as planting is delayed into late May the advantage of narrow rows is evident. There is a general trend to utilizing lower seeding rates combined with using a planter as apposed to a drill on 15 inch rows. This debate can be ongoing regarding the differences. In the end the grower needs to utilize what is available to allow for ideal final stands based on the field location and specific needs.

Extremely early and or late often times results in reduced yields however the wide planting window afforded between those times gives ample time to get the soybeans planted and growing.

The picture below is a 2012 study at Penn State whereby a variety was planted weekly from Mid-March to Mid-June. It demonstrates how the soybean plant adapts to planting date. The early plantings were a full month earlier in maturity.

Early plantings are where most yield winning entries come from the Pa Soybean Contest.

6. Foliar Nutrients

The PA Soybean On Farm Network has shown inconsistent results from applications of foliar products. However, there are field situations where plants have hidden issues and may limit yields. This often times is from low K levels however growers can determine this need through tissue testing. Gather leaves at R2 when the plant is at full flower and send to for a plant tissue test. Determine any hidden fertility issues for that field to address in the next seasons crop. Select a PDA approved foliar fertilizer or dry application with basic fertilizer to manage any micro nutrient issues

7. Pest Management

Seedling Management: For early planted soybeans prior to May 10 in many areas there has been shown in three years of PA On Farm Network testing an economic yield results as well as a significant stand savings by protecting seeds placed in a cool wet environment. In some areas its best to utilize a seed treatments with an insecticide(imadicloparid, thiomethoxym, or pyrethroid) and a fungicide for early planted soybeans in fields that have a manure history or tend to be moist or in no till conditions. As planting is delayed beyond May 10 in many areas the response to seed treatment fungicide and insecticide applications are not economic unless known pests are problematic. One key pest to manage in reduced tillage fields are slugs. A combined tactic of using a planter equipped with row cleaners and spoked closing wheels to avoid any side wall compaction, delayed or extremely early planting to plant on either side of the key hatch period(typically but not always first week of May) for slugs and combine with labeled control materials if needed will prove useful in fields that are known to harbor slugs. More research is being conducted to provide more guidance in this area.

In season Management: Economic thresholds exist for most pests mid season and are in the Agronomy Guide. In many cases arbitrary applications do not translate into economic returns. Table 1. illustrates this point. Within the PA Soybean On Farm Network over 200 replications from 2010-2016 there were only two years with an economic response and overall not enough yield benefit to pay for application and material cost. However if a pest is present and the timing is correct economic yields may result. In 2014 the PA Soybean On Farm Network selected growers with fields known to have a white mold pest issue. The results in table 2 demonstrate the response to pest management practice when indeed a problem exists. Economic results were observed in 2 out of the 3 locations.

Table 2: PA Soybean On Farm Network 2014 Soybean Response to Approach fungicide where white mold is known to be an issue in the field.

Combined results:

Cooperator

County

Treatment #

Reps

Treated

% Incidence

Untreated

% Incidence

Bu/acre Difference

Economic Return

Significance

Mervin Horst

Lebanon

Two applications

3

77.4

10

60.8

20

16.6

$119.40

P=.10LSD=6

Glen Krall

Lebanon

Single Pass at R3

3

96.2

15

82

25

14.2

$97.80

P=.10LSD=9

Kent Martin

Franklin

Single Pass

12

82.6

--

78.3

--

4.3

$8.70

No

Average

18

85.4

12.5

73.7

22.5

11.7

$75.30

P=.10LSD=10

Weed Management: Consider a pre followed by post herbicide program or ensure weeds are controlled by the time the weed height reaches 6 inches in height. In 2004 the Penn State Weed Team has documented significant weed control and yield differences from a pre followed by post herbicide management system vs a check where only a burn down followed by an in season herbicide was used to manage weeds.

8. Harvest Management

Once 95% of the pods turn brown about a week later its time to combine. Some recent work at Iowa State showed a 3.2% loss of moisture per day more than 5 times that of corn. So dry down is quick. The data also suggested about 12 days after pod maturation 13% moisture was noted over the study period.

Once moistures dip below 13% a grower grower is essentially giving the mill soybean dry matter since they will correct the moisture to 13%. Once the plants first reach harvestable moistures dry matter losses occur simply by the alternating day night and heavy dew.